Area Forecast Discussion
Issued by NWS Great Falls, MT

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483
FXUS65 KTFX 112131
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
231 PM MST THU FEB 11 2016

.DISCUSSION...

THIS AFTERNOON THROUGH SATURDAY EVENING...ONE MORE AFTN/EVE OF
PLEASANT, SPRING-LIKE CONDITIONS ACROSS OUR REGION THANKS TO THE
PERSISTENT HIGH PRESSURE RIDGE OVER THE WESTERN STATES. BUT OUR
RUN OF QUIET WEATHER WILL TRANSITION TO A MORE ACTIVE PATTERN
STARTING LATER TONIGHT. LATEST WATER VAPOR SATELLITE IMAGERY
SHOWS BROAD PLUME OF PACIFIC MOISTURE ACROSS MUCH OF
WA/OR/SOUTHWEST ID AND TRACKING STEADILY TOWARD WESTERN MT.
SHORT- TERM MODELS REMAIN IN GOOD AGREEMENT THAT THE MOISTURE
WILL MOVE EAST OF THE DIVIDE DURING THE OVERNIGHT HOURS, WITH
PRECIPITATION STARTING ALONG THE ROCKY MTN FRONT AND SOUTHWEST MT
THEN SPREADING NORTHEASTWARD INTO CENTRAL MT TOMORROW MORNING.
PRECIPITATION TYPE REMAINS THE BIGGEST CHALLENGE AS SURFACE TEMPS
WILL BE HOVERING A FEW DEGREES EITHER SIDE OF FREEZING AS THE
PRECIP ARRIVES, SUGGESTING THAT RAIN/SNOW MIX WILL BE THE
PREDOMINANT PRECIP TYPE. HOWEVER, FORECAST MODEL SOUNDINGS ALSO
HINT AT A SLIGHT CHANCE FOR FREEZING RAIN FROM NORTH OF GREAT
FALLS THROUGH CHOUTEAU COUNTY TOWARD HAVRE AND EAST TOWARD JUDITH
BASIN COUNTY. GIVEN THE LOW AMOUNTS OF LIQUID PRECIP THE MODELS
ARE INDICATING (TRACE TO A FEW HUNDREDTHS OF AN INCH) AND THE
LACK OF CONSISTENT FREEZING RAIN SIGNATURES IN THE SOUNDINGS, ANY
FREEZING RAIN THAT DOES OCCUR SHOULD BE VERY SPOTTY IN COVERAGE,
MINIMAL IN ACCUMULATION AND CAUSE ONLY VERY LOCALIZED TRAVEL
IMPACTS.

THIS INITIAL SURGE OF PRECIP WILL EXIT INTO NORTHEAST MT AND
SASKATCHEWAN FRI EVE WITH DRIER CONDITIONS TO FOLLOW THROUGH SAT
MORNING. BY MIDDAY SAT, A SHORTWAVE TROF MOVES INTO WESTERN THIRD
OF THE STATE, BRINGING ANOTHER ROUND OF SCATTERED LOWER ELEVATION
RAIN AND MTN SNOW FOR THE ROCKY MTN FRONT AND AREAS MAINLY
ALONG/SOUTH OF LINE FROM HELENA TO LEWISTOWN. THIS SYSTEM IS
CARRYING A BIT MORE MOISTURE WITH IT, SO SEVERAL SITES IN
SOUTHWEST MT MAY SEE 0.05 TO 0.15 INCHES OF PRECIP THAT WILL
TRANSLATE INTO SNOWFALLS OF ONE-HALF TO AN INCH OR TWO.
WARANAUSKAS

SATURDAY NIGHT THROUGH THURSDAY...OVERALL THE WEATHER PATTERN
WILL BE A BIT MORE ACTIVE THAN PREVIOUSLY THOUGHT OVER THE PAST
FEW DAYS. EVEN THOUGH NO MAJOR PRECIPITATION STORMS ARE
EXPECTED...SOME PRECIPITATION SHOULD BE PLANNED FOR...ALONG WITH
THE POTENTIAL FOR STRONG WINDS ON BOTH MONDAY AND TUESDAY.
SCATTERED RAIN/SNOW SHOWERS WILL AFFECT MUCH OF THE REGION
THROUGH THE EXTENDED PERIOD...WITH THE SHOWERS DECREASING IN
COVERAGE A BIT ON WEDNESDAY...ONLY TO BECOME A BIT MORE
WIDESPREAD ONCE AGAIN NEXT THURSDAY. LIQUID PRECIPITATION AMOUNTS
CONTINUE TO LOOK LOW...GENERALLY LESS THAN 0.10 INCHES EACH DAY.
ADDITIONALLY...THE POTENTIAL EXISTS FOR POSSIBLE PERIODS OF HIGH
WINDS BOTH ON MONDAY AND TUESDAY OVER NORTH CENTRAL MT. HIGH WIND
HIGHLIGHTS MAY BE NEEDED FOR PORTIONS OF THE REGION DURING THIS
PERIOD. HOWEVER...THE MEDIUM RANGE MODELS ARE NOT IN GOOD
AGREEMENT WITH THE PLACEMENT OF THE LEE SIDE TROUGH AND THE TIMING
OF THE STRONGEST MID LEVEL WINDS. CONFIDENCE IS THEREFORE ONLY LOW
TO MODERATE ON THE TIMING OF ANY POTENTIAL EVENT AT THIS TIME.
OVERALL...TEMPERATURES WILL CONTINUE TO BE ABOVE NORMAL THROUGH
THE EXTENDED...WITH AREAS OVER THE NORTHERN PLAINS HAVING THE
WARMEST TEMPERATURES. HAVE ALSO WARMED HIGH TEMPERATURES A FEW
DEGREES OVER CONSENSUS MODEL GUIDANCE FOR MONDAY/TUESDAY DUE TO
THE POTENTIAL FOR STRONGER DOWNSLOPE WINDS.
BRUSDA/COULSTON

&&

.AVIATION...
UPDATED 1801Z.

VFR CONDITIONS ARE EXPECTED AT ALL TAF SITES THROUGH
00Z/FRI...THEN FORECAST CONFIDENCE BEGINS TO DROP AFTER THIS
POINT. DESPITE THE UPPER LEVEL RIDGE IN PLACE...MOISTURE/LIGHT
PRECIP IS EXPECTED TO MOVE NE THROUGH THE RIDGE AND ACROSS
CENTRAL AND SOUTHWEST MONTANA TONIGHT THROUGH FRIDAY.
TEMPERATURES AT THE SURFACE AND JUST ABOVE THE SURFACE ARE
EXPECTED TO BE NEAR OR JUST ABOVE FREEZING WHICH LENDS TO A LOWER
CONFIDENCE FORECAST REGARDING PRECIPITATION TYPE AND AVIATION
IMPACTS. FOR NOW WENT WITH A RAIN/SNOW MIX FOR
KGTF/KCTB/KHVR/KLWT...BUT THE PRECIP TYPE WILL LIKELY NEED SOME
REFINEMENT IN LATER FORECASTS. A BRIEF PERIOD OF FZRA CANNOT BE
RULED OUT AT THE ABOVE-MENTIONED SITES BUT CONFIDENCE IS TOO LOW
TO INCLUDE IN THE TAFS FOR NOW. ACROSS SW MT...SOME POCKETS OF
FZRA CANNOT BE RULED OUT EITHER...ESPECIALLY VICINITY KHLN...BUT
CONFIDENCE REMAINS LOW IN THIS AREA AS WELL. OF NOTE...CONFIDENCE
IS HIGHER THAT MVFR OR LOWER CIGS WILL OCCUR ACROSS EASTERN
SECTIONS OF CENTRAL...ESPECIALLY IN THE VICINITY OF KHVR/KLWT AS
AN EASTERLY FLOW BRINGS LOW LEVEL CLOUDS INTO THE AREA. MARTIN

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  32  51  37  51 /  10  60  10  20
CTB  30  45  34  48 /  10  60  10  10
HLN  31  46  33  45 /  30  30  10  20
BZN  26  42  25  40 /  30  30  10  40
WEY  21  38  20  33 /  20  10  10  30
DLN  31  45  31  40 /  20  10  10  20
HVR  26  37  28  51 /  10  50  20  10
LWT  27  40  33  44 /  10  60  10  20

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

WEATHER.GOV/GREATFALLS



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